Organic, vegan and gluten-free products were once consigned to a dusty corner of alternative food shops, and considered by hoi polloi as nothing more than the gratuitous indulgence of the hippy-dippy brigade.

But in recent times, the sector has undergone a transformation as dramatic as a kaftan wearer embracing the concept of Lycra.

Over the past five years, the "free from" market has morphed from niche to mainstream as big retailers and food manufacturers clock the commercial benefits of catering to the spiralling number of us who have a food allergy or intolerance – most often to gluten, wheat and dairy products. Children are most affected, with up to 50% being diagnosed with an allergic condition. Allergy UK reports a significant increase in such conditions, partly due to diets that include a lot of processed foods and less fruit and vegetables.

One of the reasons the famous Grassroots health store at Glasgow's Charing Cross closed last month after enjoying a strong alternative presence in the city since 1977 is, somewhat perversely, down to this unprecedented proliferation. Owner Louise Duncan's decision to close was informed by the reality that the demand for the ethically-sourced, allergy-neutral food she was unique in supplying for years has now become readily available in delis, high-street retail outlets and even supermarkets. "When we started out, nobody else was doing what we were doing, and now it's become the norm," she said.

Greencity Wholefoods, on the other hand, a workers' co-operative which has been sourcing and supplying gluten-free and vegan products from Glasgow's east end to mainsteam retail and catering outlets all over the country since 1978, continues from strength to strength. New products are coming in from a variety of dedicated artisan manufacturers, and this month fruit-flavoured organic porridge for children, sticky toffee pudding, dairy-free yoghurt are among the gluten-free offers; and organic ketchup and tofu cottage cheese are among the new vegan items.

Scottish producers are also getting in on the act. A newcomer to the market, which is already attracting plaudits and is to start supplying the international Compass catering group, is the Pulsetta range of gluten-free vegan bread rolls and sliced loaves from Plenta Foods in Aberdeen. Made with a range of milled pulses, they are gluten, wheat, lactose, milk, dairy, egg, soy, or any other major food allergen-free.

A new range of pizzas, invented by Eat Balanced of Glasgow with the support of nuritionist Mike Lean to provide healthy proportions of calories, proteins, carbohydrates, fats, salts, sugar, fibre, vitamins and minerals, is on sale in Sainsbury's, Asda and through Ocado. Each individual pizza is designed to provide about 30% of the guideline daily amounts for the ever-hungry teenager and the harassed parent.

Individuality is the name of the game when it comes to the modern allergy-ridden consumer, with many tailor-made diets. It's like a free-from version of flower power. The brown-rice-and-sandals set swapping recipes with the Jimmy Choo chavs? A sign of the times indeed.